Inferior Vena Cava Distensibility Index
Estimates fluid responsiveness from respiratory variation in inferior vena cava diameter.
When to use
Ventilated and sedated patients with hemodynamic instability when assessing fluid responsiveness.
Pearls and pitfalls
- The index uses the variation between maximum and minimum diameter during the respiratory cycle.
- The measurement depends on mechanical ventilation, sedation and an adequate acoustic window.
- Arrhythmias, spontaneous breathing and elevated intra-abdominal pressure reduce reliability.
- The result does not replace global perfusion assessment and the clinical response to a fluid challenge.
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Formula
Index (%) = (maximum diameter − minimum diameter) / minimum diameter × 100.
Evidence
Index evaluated in ventilated septic patients, with an 18% threshold to predict fluid responsiveness.
References
- Barbier C, Loubieres Y, Schmit C, et al. Respiratory changes in inferior vena cava diameter are helpful in predicting fluid responsiveness in ventilated septic patients. Intensive Care Med. 2004;30(9):1740-1746. doi:10.1007/s00134-004-2259-8
Frequently asked questions
What is Inferior Vena Cava Distensibility Index?
Estimates fluid responsiveness from respiratory variation in inferior vena cava diameter. Ventilated and sedated patients with hemodynamic instability when assessing fluid responsiveness.
How is the result calculated?
Index (%) = (maximum diameter − minimum diameter) / minimum diameter × 100.
How should the result be interpreted?
Index evaluated in ventilated septic patients, with an 18% threshold to predict fluid responsiveness.
What are the sources?
Barbier C, Loubieres Y, Schmit C, et al. Respiratory changes in inferior vena cava diameter are helpful in predicting fluid responsiveness in ventilated septic patients. Intensive Care Med. 2004;30(9):1740-1746.